SR USA class
|Southern Railway USA class |
|USA class locomotive No.65 in Southern Railway livery|
|Builder||Vulcan Iron Works, USA (13)
H. K. Porter, Inc., USA (1)
|Gauge||4 ft 8 1⁄2 in (1,435 mm)|
|Driver diameter||54 in (1.372 m)|
|Wheelbase||10 ft 0 in (3.05 m)|
|Length||29 ft 8 in (9.04 m)|
|Locomotive weight||41 tons 9 cwt (42.3 tonnes)|
|Fuel capacity||17.8 cwt (0.9 tonnes)|
|Water capacity||1,000 imp gal (4,500 l; 1,200 US gal)|
|Boiler pressure||210 psi (1.45 MPa)|
|Cylinder size||16½ × 24 in (419×610 mm)|
|Valve type||8 inches (203 mm) piston valves|
|Tractive effort||21,600 lbf (96.08 kN)|
|Power class||BR: 3F|
|Number in class||14 (plus one bought for spares)|
Construction history 
Thirteen out of the Southern's 15 locomotives (14 for traffic plus one for spares) were built at the Vulcan Iron Works in Wilkes-Barre, Pennsylvania in 1942 to the design specifications of the USATC by Col. Howard G. Hill. The remaining two were built by H. K. Porter, Inc of Pittsburgh. Overall, 382 of the class had been ordered from Davenport Locomotive Works of Davenport, Iowa, H. K. Porter and Vulcan Iron Works.  They were shipped to Great Britain in 1943 and stored awaiting the invasion of Mainland Europe, after which many were shipped to Europe, but others, including those purchased, had hardly been used and were lying around in dumps awaiting disposal.
The key to their success, after being acquired by the Southern Railway, was their short wheelbase, which was able to negotiate the tight curves found at Southampton Docks. They were also powerful, able to haul heavy freight trains as well as full-length passenger trains in the harbour area.
After the war they replaced ageing B4, D1 and E1 class tanks in Southampton Docks at the recommendation of Oliver Bulleid. Steam heating, vacuum ejectors, sliding cab windows, additional lamp irons and new cylinder drain cocks had to be added for them to operate on British metals. More modifications became necessary once the locomotives started to enter traffic, including large roof-top ventilators, British-style regulators (as built they had US-style pull-out ones), three rectangular cab-front lookout windows, extended coal bunkers, separate steam and vacuum brake controls and wooden tip-up seats. This meant that it took until November 1947 for the entire class to be ready for work.
Livery and numbering 
War Department and Southern 
Livery during the Second World War was USATC black with white numbering and lettering 'Transportation Dept.' on the watertank sides. Prior to nationalisation, the locomotives were painted in Southern black livery with 'Southern' in "Sunshine Yellow" lettering.
Thirteen of the locomotives were re-numbered 61-73 by the Southern; 4326 retained its War Department number instead of being renumbered 74, while the locomotive used for spares was not numbered.
Post-1948 (nationalisation) 
The class was allocated the BR power classification 3F, whilst the lettering on the tank sides was changed to 'British Railways' during 1948 as a transitional measure. Finally, the class was outshopped in BR Departmental Malachite livery, with BR crests on the watertank sides and numbers on the cab sides.
Under the BR Standard numbering system they were renumbered 30061-30074.
Operational details 
They were used for shunting in Southampton Docks and replaced the elderly LSWR B4 Class 0-4-0T tank locomotives, many of which required new boilers. Although they were excellent performers, their austerity construction meant that they deteriorated very quickly. Their steel fireboxes rusted and fatigued quickly, and this came to a head in 1951 when several had to have new fireboxes constructed.
Telephones were installed on the footplate to improve communication on the vast network of sidings at Southampton. They were replaced by British Rail Class 07 diesel-electric shunters, introduced in 1962. Nine remained in departmental use within the military and National Coal Board, and five survived until the end of steam on the Southern Region, in 1967, in departmental use at workshops and loco sheds.
Four examples have been preserved in England:
- 30064 Bluebell Railway (Awaiting major overhaul)
- 30065 Kent and East Sussex Railway (Operational)
- 30070 Kent and East Sussex Railway (Undergoing major overhaul)
- 30072 Keighley and Worth Valley Railway (Awaiting major overhaul)
plus two ex-JŽ class 62 locomotives, built to a broadly similar design, which are to be converted to British USA Class specifications.
In fiction 
Further reading 
- Sprenger, J. Howard; Robertson, K.J.; Sprenger, C.C. (23 July 2004). The Story of the Southern USA Tanks. Southampton: KRB Publications. ISBN 978-0-9544859-3-1.
- Ian Allan ABC of British Railways Locomotives, winter 1959-60 edition
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